This invention relates to an optical semiconductor device, a socket for mounting the optical semiconductor device thereto, and an optical semiconductor unit.
Formerly, an LED (Light Emitting Diode) device as a typical optical semiconductor device was fixed to a substrate by soldering and used.
However, if the LED device is fixed to the substrate, replacement of the LED device is difficult and troublesome. In view of the above, an LED device of a replaceable connector type has been proposed as disclosed in JP-A-2001-24216 (Patent Document 1) and JP-A-2008-288221 (Patent Document 2).
It is said that the LED device generates less heat as compared to a common light source using a filament or the like. However, in recent years, along with an increase in luminance, a driving current is increased and, as a result, heat generated from an LED is increasing. This brings about a problem that the heat generation increases a temperature of the LED device to cause deterioration of the LED device. In order to solve the above-mentioned problem, proposal is made of an LED socket having a structure in which an entire substrate with an LED device is brought into tight contact with a heat sink to be cooled, as disclosed in JP-A-2004-265626 (Patent Document 3).